07-09-2012 12:28 PM
Using Norton AntiVirus, I did a manual scan of my Mac hard drive and LaCie external hard drive. The Mac scan went well. I have the LaCie external partitioned into 2 parts, one for the Mac Time Machine backup.
When I did a separate scan of this Time Machine backup, Norton reached the point where it had scanned all the files, but then it kept going, scanning more files than it said were on the backup partition. I finally had to cancel the scan.
Why did this happen? What should I do about it? Thanks.
Solved! Go to Solution.
07-09-2012 12:58 PM - edited 07-09-2012 12:59 PM
Unfortunately, the AntiVirus software can't properly count files in Time Machine backups, and ends up counting millions and millions past the real number of files.
The reason is that the scan counts (and scans) each file multiple times, because the AntiVirus software doesn't know how to distinguish links to a single file that never changed from backup to backup.
The scan will also often take days, because it's scanning the same files over and over, so most people just end up cancelling it merely because it takes so long to finish.
Symantec's "solution" is to recommend that you exclude scanning Time Machine volumes. This isn't really reassuring, especially if a virus got backed up in the past, but this long-standing bug has never been fixed yet.
07-09-2012 01:05 PM
Many thanks for your quick reply. Sounds like there's not much I can do about this, but it is nice to know I'm not alone!
08-19-2012 09:11 AM
I have the same problem (I'm on Day 2!) and can see that excluding Time Machine works in future. But should I just let this thing run all the way to the end (or will it ever end?) and then exclude? Or should I cut if off now and then make sure that TM excluded in future? It keeps picking up W32.Cridex, Trojan.Smoaler and MacProtector... then deleting or quarantining files or saying Virus Fully Repaired. Been a Mac user for ages and the very first time I bought a machine and installed antivirus software it had a worm. So haven't used once since but know I should start:-) Thanks for any advice.
08-21-2012 09:44 PM
I want to be clear--are you saying that scanning your Time Machine drive has not completed after a long time but it did find issues?
We actually just tried this today, and couldnt reproduce it. Although it took a long time (about 8 hours) our scan of a Time Machine backup completed successfully. However perhaps when it finds something to quarantine/repair, the scan goes haywire.